Re: [PATCH v3 4/4] mm/page_owner: document page_owner filter features

[zhen.ni]

在 2026/4/29 09:35, SeongJae Park 写道:
> On Tue, 28 Apr 2026 15:11:12 +0800 Zhen Ni <zhen.ni@xxxxxxxxxxxx> wrote:
>
> > Add documentation for the page_owner filter functionality, including:
> > - Print mode filter (full stack vs stack handle)
> > - NUMA node filter (single node, multiple nodes, ranges)
> > - Usage examples for both filters
> >
> > Signed-off-by: Zhen Ni <zhen.ni@xxxxxxxxxxxx>
> > ---
> >
> > Changes in v3:
> > - New patch to document filter features as requested by Andrew Morton
> > ---
> >   Documentation/mm/page_owner.rst | 55 ++++++++++++++++++++++++++++++++-
> >   1 file changed, 54 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst
> > index 6b12f3b007ec..6261366d33fe 100644
> > --- a/Documentation/mm/page_owner.rst
> > +++ b/Documentation/mm/page_owner.rst
> > @@ -74,7 +74,17 @@ Usage
> >   
> >   3) Do the job that you want to debug.
> >   
> > -4) Analyze information from page owner::
> > +4) (Optional) Use filters to focus on specific memory allocations::
> > +
> > +    cd /sys/kernel/debug/page_owner_filter
> > +
> > +    # Print only stack handles instead of full traces
> > +    echo 1 > print_mode
> > +
> > +    # Filter by NUMA nodes
> > +    echo "0,2-3" > nid
>
> Nit.  Other parts of the document uses tab for the indentation, while the above
> new snippet is using four spaces.  How about using tab for the consistency?
>
> > +
> > +5) Analyze information from page owner::
> >   
> >   	cat /sys/kernel/debug/page_owner_stacks/show_stacks > stacks.txt
> >   	cat stacks.txt
> > @@ -238,6 +248,49 @@ Usage
> >   				./page_owner_sort <input> <output> --tgid=1,2,3
> >   				./page_owner_sort <input> <output> --name name1,name2
> >   
> > +Page Owner Filters
> > +==================
> > +
> > +The page_owner feature provides filtering capabilities to focus on specific
> > +memory allocations (e.g., by NUMA node). Filters are controlled through debugfs
> > +files in ``/sys/kernel/debug/page_owner_filter/``.
> > +
> > +Print Mode Filter
> > +-----------------
> > +
> > +The ``print_mode`` file controls the level of detail in stack trace output.
> > +
> > +Available modes:
> > +
> > +- ``0`` (default): Print full stack traces
> > +- ``1``: Print only stack handles
> > +
> > +The ``print_mode=1`` output format::
> > +
> > +    Page allocated via order 0, mask 0x42800(GFP_NOWAIT|__GFP_COMP),
> > +    pid 1, tgid 1 (systemd), ts 349667370 ns
> > +    PFN 0xa00a2 type Unmovable Block 1280 type Unmovable
> > +    Flags 0x33fffe0000004124(...)
> > +    handle: 17432583
>
> Tab for indentation?
>
> > +
> > +To retrieve the full stack trace for a handle, use::
> > +
> > +    cat /sys/kernel/debug/page_owner_stacks/show_stacks_handles
>
> Tab?
>
> > +
> > +NUMA Node Filter
> > +----------------
> > +
> > +The ``nid`` file filters pages by NUMA node. This is useful for NUMA-aware
> > +environments to analyze node-specific memory allocation.
> > +
> > +Supported input formats:
> > +
> > +- Single node: ``echo "2" > nid``
> > +- Multiple nodes: ``echo "0,2,3" > nid``
> > +- Node range: ``echo "0-3" > nid``
> > +- Mixed format: ``echo "0,2-4,7" > nid``
> > +- Disable filter: ``echo "-1" > nid``
> > +
> >   STANDARD FORMAT SPECIFIERS
> >   ==========================
> >   ::
> > --
> > 2.20.1
>
>
> Thanks,
> SJ
I will fix all instances to use tab .

Thanks,
Zhen